1. Field of the Invention
The present invention relates to a rare-earth sintered magnet and a rotator and a reciprocating motor which are equipped therewith.
2. Related Background Art
Rare-earth sintered magnets mainly composed of R—Fe—B-based alloys having rare-earth elements as their constituent elements have been utilized as permanent magnets in various fields because of their favorable magnetic characteristics. Such rare-earth sintered magnets tend to corrode easily because of the rare-earth elements contained therein.
Therefore, in order to inhibit magnetic characteristics from being lowered by corrosion, it has been tried to produce rare-earth sintered magnets by using rare-earth alloy powders whose surfaces are provided with diffusion layers made of nitrogen or carbon or form protective films such as plating layers on surfaces of rare-earth sintered magnets, for example, so as to improve their resistance to corrosion. For example, the following Patent Literature 1 proposes to let a rare-earth sintered magnet contain nitrogen and carbon, thereby improving the corrosion resistance.    Patent Literature 1: Japanese Patent Application Laid-Open No. 4-242902